Troubleshoot with web-based online tools
There are many websites available that provide free services for troubleshooting DNS issues. This is the easiest option to find reason for DNS failure.
Examples:
- To check the health of your domain DNS and mail server reports, you can visit – https://intodns.com
- To check your domain names current IP address and DNS record information from different locations, you can check it from – https://www.whatsmydns.net/ This website helps you to check the current state of DNS propagation.
- You can check if private nameservers are registered correctly or not using this website – https://www.internic.net/whois.html Search for nameservers, the result will come with your IP address if you add private nameservers correctly. Server Name: NS1.EUROVPS.COM IP Address: 77.235.63.12
Troubleshoot with command Line tools
Don’t want to use an online tool? No problem, there are many ways that you can troubleshoot using the command line like a pro.
Troubleshooting DNS issues on Linux or Mac
Dig command
This tool is the favorite/powerful command-line tool for DNS troubleshooting and helps you dig into DNS issues. It is installed by default on many operating systems, including Linux and Mac OS X.
Format : dig hostname
[root@eurovps ~]# dig eurovps.com
Here is the example with website google.com
[root@eurovps ~]# dig google.com ; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7_5.1 <<>> google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39888 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 130 IN A 216.58.212.174 ;; Query time: 0 msec ;; SERVER: 62.212.64.122#53(62.212.64.122) ;; WHEN: Sun Mar 03 07:16:53 EET 2019 ;; MSG SIZE rcvd: 55
dig +trace
We can perform a trace on the DNS lookup path with the +trace option.
Format : dig +trace domainname
[root@eurovps ~]# dig +trace eurovps.com
Let’s use dig +trace www.google.com as our command with a domain name and we can see what actually happens
[root@eurovps ~]# dig +trace google.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6_8.4 <<>> +trace google.com ;; global options: +cmd . 498137 IN NS h.root-servers.net. . 498137 IN NS i.root-servers.net. . 498137 IN NS a.root-servers.net. . 498137 IN NS l.root-servers.net. . 498137 IN NS k.root-servers.net. . 498137 IN NS d.root-servers.net. . 498137 IN NS e.root-servers.net. . 498137 IN NS f.root-servers.net. . 498137 IN NS m.root-servers.net. . 498137 IN NS b.root-servers.net. . 498137 IN NS j.root-servers.net. . 498137 IN NS g.root-servers.net. . 498137 IN NS c.root-servers.net. ;; Received 508 bytes from 77.235.33.38#53(77.235.33.38) in 15 ms com. 172800 IN NS a.gtld-servers.net. com. 172800 IN NS b.gtld-servers.net. com. 172800 IN NS c.gtld-servers.net. com. 172800 IN NS d.gtld-servers.net. com. 172800 IN NS e.gtld-servers.net. com. 172800 IN NS f.gtld-servers.net. com. 172800 IN NS g.gtld-servers.net. com. 172800 IN NS h.gtld-servers.net. com. 172800 IN NS i.gtld-servers.net. com. 172800 IN NS j.gtld-servers.net. com. 172800 IN NS k.gtld-servers.net. com. 172800 IN NS l.gtld-servers.net. com. 172800 IN NS m.gtld-servers.net. ;; Received 488 bytes from 198.97.190.53#53(198.97.190.53) in 159 ms google.com. 172800 IN NS ns2.google.com. google.com. 172800 IN NS ns1.google.com. google.com. 172800 IN NS ns3.google.com. google.com. 172800 IN NS ns4.google.com. ;; Received 276 bytes from 192.31.80.30#53(192.31.80.30) in 31 ms google.com. 300 IN A 172.217.20.110 ;; Received 44 bytes from 216.239.32.10#53(216.239.32.10) in 4 ms
Query DNS from Specific Name Server
We can specify a name server to send the query to with the @ symbol, followed by the hostname or IP address of the name server.
[root@eurovps ~]# dig eurovps.com @ns1.eurovps.com
Here is the example for google.com from nameserver ns1.google.com
[root@eurovps ~]# dig google.com @ns1.google.com ; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7_5.1 <<>> google.com @ns1.google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47655 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 300 IN A 172.217.19.206 ;; Query time: 4 msec ;; SERVER: 216.239.32.10#53(216.239.32.10) ;; WHEN: Sun Mar 03 07:13:40 EET 2019 ;; MSG SIZE rcvd: 55
Troubleshooting DNS issues on Windows
nslookup
To perform a DNS query on a Windows computer, follow these steps:
Go to Start->Run and type in “cmd” then click “OK.”
In the command prompt, execute the following command with the domain/hostname that you want to check.
nslookup eurovps.com
Format : nslookup hostname
C:\Users\eurovps>nslookup eurovps.com
Example with google.com
C:\Users\eurovps>nslookup google.com
10.in-addr.arpa
primary name server = bhdns.mydomain.ca
responsible mail addr = bhdns.mydomain.ca
serial = 1
refresh = 28800 (8 hours)
retry = 7200 (2 hours)
expire = 864000 (10 days)
default TTL = 86400 (1 day)
Server: UnKnown
Address: XXX.XXX.XX.XX
Non-authoritative answer:
Name: google.com
Addresses: 2404:6800:4007:80d::200e
172.217.163.110
C:\Users\evs_proust
To check a specific DNS record, you need to specify the nslookup command, an optional record type (for example, A, MX, or TXT), and the hostname that you want to check.
Note: DNS records can take up to 48 hours to propagate worldwide.